Empty string: Difference between revisions

=={{header|Icon}} and {{header|Unicon}}==

Icon and Unicon don't have special syntax for null strings but can produce them in several ways

<lang Icon>s := "" # null string

s := string('A'--'A') # ... converted from cset difference

s := char(0)[0:0] # ... by slicing

s1 == "" # lexical comparison, could convert s1 to string

s1 === "" # comparison won't force conversion

*s1 = 0 # zero length, however, *x is polymorphic

*string(s1) = 0 # zero length string

s1 ~== "" # non null strings comparisons

s1 ~=== ""

*string(s1) ~= 0

s := &null # NOT a null string, null type

/s # test for null type

\s # test for non-null type </lang>